GIT Drugs Flashcards
Anabolic Steroids
Used as an appetite stimulant
- Testosterone
Mirtazapine
Really good appetite stimulant for both dogs and cats
- potent antagonist of 5-HT2 receptor and this likely causes the increase in appetite
Comes in oral tablet –> cats can be difficult so can get compounded transdermal formulation
Common to see increase in vocalization and interaction w/ drug
- warn owner’s of these behavioural changes and that it’s normal (actually a good indicator that the drug is being absorbed, especially for transdermal gel)
Glucocorticoids
As an appetite stimulant Polyphagia is common side effect - more often in dogs than cats - transient effect that may only last a few days-weeks - often used in palliative cases
Apomorphine
Emetic
- dopamine agonist in CRTZ
- really effective for dogs but less in cats
- administered in conjunctiva or IV -> stim vomiting w/in mins
Other Emetics
a2-agonists –> xylazine or dexmed
some opioids -> hydromorphone
Hydrogen Peroxide -> not very effective but clients can perform at home
Metoclopramide
Anti-emetic
- Low doses: inhibits dopamine in CNS
- peripheral prokinetic effect -> increases gastric and upper duodenal emptying
- high doses: inhibits serotonin receptors in CRTZ
Extrapyramidal effects
Also used as has prokinetic effect for gastric motility = increases gastric and upper duodenal emptying and increases gastroesophageal sphincter tone
- stims serotonin 5-HT4 receptor
- megaesophagus, post-op GDV
- make sure there is no GI obstruction
Odansetron
Anti-emetic
- Serotonin antagonist -> inhibits 5-HT3 receptor on vagal nerve and CRTZ
Useful as anti-emetic in chemo
- bc of the serotonin released due to cytotoxic drugs
Maropitant (Cerenia)
Most effective anti-emetic
Neurokinin/NK1 receptor antagonist
- lots of mechanisms of action to prevent vomiting thru the NK1 receptor
For acute vomiting and motion sickness in dogs
- oral tablets (dogs only)
- injectable (dogs and cats)
Adverse Effects
- cause bone marrow hypoplasia in young pups (not for parvo dogs < 16wks)
No consistent analgesic or anti-inflammatory effect noted
Anti-emetics for Parvo-induced emesis
Metoclopramide
Odansetron
Maropitant
Omeprazole (Gastrogard)
Inhibits gastric secretions –> HCl
- for ulcer tx and can help prevent ulcers
Hypergastrinemia -> occurs w/ reduced gastric acid -> leads to mucosal cell hyperplasia, rugal hypertrophy, and carcinoids
CYP-enzyme inhibitor
Misoprostol
Synthetic PGE analogue -> stims bicarb and mucus secretion
- increases mucosal blood flow
- decreases vascular permeability
- increases cellular proliferation and migration
Effective as preventative for NSAID-induced ulcers in dogs
Cisapride
Used as prokinetic drug as motility-modifying
- only in compounded product
Cats -> increase sm m motility in stomach, SI and colon
- megacolon
Dogs -> increase sm m motility throughout GIT
Horses -> tx of ileus after abdominal surgery
ADR
- Cardia ADRs = arrhythmias and CYP drug interactions
- no ADR in cats or dogs yet but doesn’t mean they won’t happen
Loperamide
Anti-diarrhea
- only get opioid effects in GIT and don’t see CNS analgesia or resp depression
Don’t use w/ infectious diarrhea or in known ABCB-1 mutant dogs
Polyethylene glycol/PEG
Tx of constipation
- hyperosmotic laxatives = drawing fluid into GI lumen to stim motility
Metronidazole
Tylosin
Tx of Chronic Colitis
M -> antimicrobial for giardia and anaerobes
T - macrolide that have some antimicrobial and anti-inflammatory effect
